1. Field of the Invention
The present invention relates to a plug connector with a locking mechanism, which will be locked in a receptacle connector when it is inserted into the receptacle connector and can be withdrawn out of the receptacle connector when an unlocking operating is performed on the plug connector. The invention further relates to a plug connector housing with a locking mechanism as a component thereof.
2. Related Art
Japanese Patent Publication 3094668 discloses a connector with a locking mechanism comprising a plug connector, a molded cover enclosing the plug connector, lock levers cantilevered respectively on the inward faces of both side walls in the width direction of a cover body constituting the molded cover, and a jack connector corresponding to the plug connector. The connectors are locked together or unlocked by fitting or releasing hooks provided on the other ends of the lock levers and fitting parts provided on the jack connector at positions corresponding to the hooks. The catching of the hooks on the fitting parts will be released when tongues formed by key-shaped slits made in the side walls of the cover body are pressed from outside the undergo inwardly directed elastic deformation.
Japanese Utility Model Unexamined Publication Heisei 3-16674 discloses a locking mechanism of a connector comprising a cable-side body for receiving a socket made of an insulator for holding one set of contacts for electrical connection, and a stand-side member for receiving a socket made of an insulator for holding the counterpart set of contacts. Inner walls are provided on both sides inside the casing of the cable-side body and extend linearly in the longitudinal direction. Outer walls limit the outer side of the casing. Lock plates are provided in spaces between the inner walls and the outer walls. Portions of the lock plates close to first ends thereof make point contact with protrusions provided on the inner walls. Fitting protrusions are provided by making the other second ends of the lock plates protrude outwardly from the outer walls of the casing so that the protrusions can fit into openings in the outer walls of the stand-side member. Finger-shaped parts protrude inwardly from the intermediate parts of the lock plates to contact the outer walls of the inner walls to constantly position the fitting protrusions outside through spring action. A cover member facing finger-pressing parts is provided for controlling the finger-shaped parts from the outside of the casing of the cable-side body.
Japanese Patent Unexamined Publication 2002-190351 discloses an electric connector arrangement comprising a first connector and a second connector for fitting together in a first direction and having a lock for locking the first connector and the second connector together. The first connector is provided with a lock piece and an unlocking arm for undoing or releasing the fitting of the lock piece, which is formed into an approximately L-shape having a fitting part on one end thereof for fitting with a fitting part of the second connector and a protruding part on the other end thereof for contacting a cam of the unlocking arm. The second connector is provided with a metallic shell having a catching part for fitting with the fitting part. When the first connector and the second connector are fitted together, the unlocking arm will be displaced into a second direction crossing the first direction so as to make the cam and the protruding part contact with each other, to displace the lock piece into a third direction crossing the first and second directions and undo or release the fitting between the fitting part and the catching part.
In the case of the connector with the locking mechanism of Japanese Patent Publication 3094668, the lock levers extend, inside the mold cover, on both sides of the plug connector from the rear to the front of the plug connector, and the hooks are released from the fitting parts of the counterpart jack connector by pressing the tongues with one's fingers to apply forces to the intermediate parts of the lock levers. In the case of the connector of Japanese Utility Model Unexamined Publication Heisei 3-16674, the lock plates extend, inside the casing of the cable-side body, on both sides of the socket from the rear to the front of the socket, and unlocking is effected by pressing the finger-pressing parts with one's fingers to apply forces to the intermediate parts of the lock plates so as to remove the protrusions for fitting from the openings of the counterpart stand-side member. As for connectors of this kind, it is keenly desired to minimize the forces required for unlocking. To solve this problem, the root end of the lock lever or the root end of the lock plate may be extended toward the rear of the plug connector or the socket. Or the point of action in which the force is applied to the lock lever or the lock plate may be shifted closer to the front of the plug connector of the socket. However, when the former measure is taken, the connectors will get larger in size, contrary to the efforts of making the connectors more compact. When the latter measure is taken, the tongue or the finger-pressing part is brought closer to the counterpart jack connector or socket, which makes it very difficult or impossible to unlock by pressing the tongues or the finger-pressing parts with one's fingers when the counterpart jack connector or socket is mounted in a narrow space leaving only a tight work space.
The connector of Japanese Patent Unexamined Publication 2002-190351 differs in the structure of the locking mechanism from the connectors of Japanese Patent Publication 3094668 and Japanese Utility Model Unexamined Publication Heisei 3-16674, the lock pieces, however, extend on both sides of the plug connector from the rear to the front, and the fitting parts thereof are released from the fitting parts of the counterpart receptacle connector by pressing the unlocking arms with one's fingers to apply forces to the protruding parts of the lock pieces. Accordingly, when the root ends of the lock pieces are extended toward the rear of the plug connector, the connectors will get larger, contrary to the efforts of making them more compact. When the unlocking arms are extended toward the front of the plug connector for the same purpose, it will pose a problem that it is very difficult or impossible to unlock by pressing the unlocking arms with one's fingers when the counterpart receptacle connector is mounted in a narrow space with a tight working space. Moreover, as the fitting part of the locking piece fits with the fitting part of the receptacle connector by being displaced in the thickness direction of the plug connector, this detracts from the efforts of reducing the plug connector and the receptacle connector in thickness.